In 2000, the Centers for Medicare and Medicaid Services (CMS), formerly known as the Health Care Financing Administration (HCFA) 2000 ESRD Clinical Performance Measures (CPM) Project, was expanded to obtain demographic characteristics and clinical information on all adolescent (age > or =12 years, <18 years) patients receiving in-center hemodialysis on 31 December, 1999. Of the 486 patients identified, 433 (89%) had the minimum required data submitted. Demographic characteristics included mean age of 15.8 years (+/-1.6 years). Forty-nine percent were white, 42% black; 21% were Hispanic. Congenital/urologic disease and focal and segmental sclerosis were the leading causes of end-stage renal disease. Forty-one percent had a catheter as their dialysis access, while 37% had an AV fistula and 22% an AV graft in place. The mean Kt/V was 1.47 (+/-0.38) and 79% had a mean calculated Kt/V> or =1.2, although residual renal function was not included in this measurement. After multivariate logistic regression, male gender and black race were among the factors predictive of mean calculated Kt/V<1.2. The mean serum albumin was 3.85 g/dl (+/-0.51) in patients with bromcresol green measurements and 3.62 mg/dl (+/-0.52) in patients with bromcresol purple measurements. The mean hemoglobin was 10.99 g/dl (+/-1.6) and 55% had a mean hemoglobin > or =11 g/dl. After multivariate logistic regression, lower epoetin dose and mean serum albumin > or =3.5/3.2 g/dl (BCG/BCP) remained predictive of mean hemoglobin > or =11 g/dl. These data provide important information about the clinical status of adolescent hemodialysis patients in the United States. Continued data collection and analyses are planned to identify areas for potential improvement in patient care.